Look. Design specifications are set so different parts of a complex program or different applications running simultaneously do not interfere. Nexus runs over the Windows GUI. Your findings that changing desktop configurations in Windows start the problem, also says that the Windows handling of the display causes the problem. Additionally, the fact that Skagon was unable to reproduce the problem with the un-updated system, also says that the update caused the problem. If you want to report something to someone, you should do it to Microsoft.

In most circumstances when encountering a malfunction it is not unreasonable to blame it on the little guy. However, very recently Microsoft released an update that they called off the next day or two, advising simply that it should be deleted. Policy changes at Google in 2010, resulted in three consecutive implementations messing up search results for legitimate and non fraudulent sites, and three consecutive waves of protest, taking Google's PR weeks to calm everyone down on assurances that those problems would be sorted out. Facebook, got quite bad PR on development and policy errors. You are certainly aware of all of this. Blaming the little guy up to a point ought to make sense because these companies are supposed to hire the best people in the industry. It certainly does not make them immune to error. Not the kind of convoluted subtle error that takes a while to define in terms of events and configurations, but the kind of error that emerges the very next day and the whole world crashes into.

It would be unwise for Winstep to try a workaround on this. Among other reasons, and the main one being, that it would have to overstep specification boundaries, like I told you before, potentially interfering with other applications and services running in the system.

If you still want to file a bug report with Winstep, you just did. Your comments, remarks and instructions are duly noted and on record in this thread.

There is no bug report "form". Actually, the developer (Jorge) has been notified already.

Incidentally, I did some tests on that testing PC of mine. It seems the bug is now reproducible even when using Workshelf. I tried many different settings, to no avail. So, I guess this is an official bug.
The strange thing is, I still don't get it on my main PC... (not that I'm complaining)

I'll keep you updated.

Good news (for me at least, not so much for developers... extra work...) Thank you for your serious support.

Strange you can't reproduce the bug:
1. run Nexus + ClipX (freeware, can download also from Softpedia)
2. change Windows background or set auto-cycle
3. click on desktop and call ClipX menu

You can reproduce it also with Windows Live Mail (Microsoft Windows Essentials) clicking with RMB on the WLM traybar icon repeatedly (context menu will pop-up and also ghost windows/icon in the toolbar)...

skagon / hexaae one suggestion compare your hardware. just a thought since it seems the two of you tried everything else.

No, I don't think so... I've reproduced this on completely different machines. The repro situation is not so common and you have to follow some specific steps so many users won't notice this.
I'm sure the capable Winstep coders will find the problem...